Strategy #13 Know how to work with averages:

• Average and Mean are the same thing in this test.
• If the individual quantities are not known but their average is, you can let the average       value stand in for each of the unknown quantities.

Sometimes the average for a group of objects is given, and the average of a smaller group within that group is also given but we don’t know their individual values. Let the objects in the smaller group all equal their given average. This lets us not worry about individual values.

Example: Six children have an average height of 62 inches. Five of those children have an average height of 60 inches. What is the height of the sixth child?

The height of the sixth child is 72 inches.
• When you know the number of things, and you know their average, multiply these two values to get what the things add up to. From the example above, the heights of 6 children added together was: